Burg Breisach, Medieval castle ruins in Breisach, Germany

Burg Breisach consists of medieval fortress ruins perched on the Münsterberg plateau above the town. Stone walls and a wide moat formed the main defenses of this stronghold.

Built around the end of the 12th century, probably by Berthold V of Zähringen, the castle was expanded by the Habsburgs in 1294 and made an imperial castle in 1315. Emperor Charles V appointed Lazarus von Schwendi as castellan in 1552, and he strengthened the fortifications until his death in 1583. It was damaged in the 1633 siege and after the 1638 Battle of Wittenweiher, then slighted in 1741 under Maria Theresa; the last remains of the residential tower were removed in 1793.

The castle gave its name to the Breisach Burgvogt office: Emperor Charles V appointed Lazarus von Schwendi as Burgvogt in 1552, and he fortified the site until his death in 1583. A model of the fortress is kept in the town museum in the Rheintor, showing the rectangular keep and the 20–24 m wide neck ditch.

A detailed model of the original structure is displayed at the city museum in Breisach, offering clear insight into how it looked. Exploring the ruins themselves requires sturdy footwear since the ground is uneven.

The rectangular keep measured 24 by 17 metres, stood 27 to 30 metres high and had walls 3 metres thick. The neck ditch defending it was 20 to 24 metres wide and 12 metres deep. A model of the fortress is shown in the town museum in the Rheintor.